[Objective] The area of coastal saline soil is recognized as an important land resource with utilization value for agriculture. However, coastal mudflat area is usually characterized by poor plant growth and low microbial activity due to its high salinity suppressing most crops via the high osmotic stress, nutrient deficiency, toxicity and poor physical soil conditions. Soil microbes like Trichoderma spp. play a significant role in assisting plants to tolerate salinity stress. The present study aimed to investigate the effect of two Trichoderma-enriched bio-organic fertilizers on the yield and quality of cabbages (Brassica oleracea L.) grown in coastal saline soil as well as their effect on soil nutrient availabilities.[Method] Field and pot experiments were carried out with eight treatments:100% chemical fertilizer (CF), 30% bio-organic fertilizer plus 70% chemical fertilizer, 60% bio-organic fertilizer plus 40% chemical fertilizer, 100% bio-organic fertilizer (without chemical fertilizers), and using the non-fertilization treatment as the control (CON). The two bio-organic fertilizers were respectively prepared with strains of Trichoderma guizhouense NJAU 4742 (which is commercially available in China as a plant-growth-promoting agent) and T. arenarium 1A131 (which was previously isolated from saline mudflat of Dafeng, Jiangsu). The nutrient load of the seven fertilization treatments was set up to equal in the aspect of the contents of total N, P and K.[Result] Results obtained from both the field and pot experiments demonstrated that there was no significant difference in the effect of the two bio-organic fertilizers. Compared to the non-fertilized control (CON) and the full chemical fertilization (CF), 30% or 60% bio-organic fertilizer significantly increased the contents of nitrate N and available P in soil. The treatment of 60% bio-organic fertilizer plus 40% chemical fertilizer influenced the cabbage growth by significantly (P< 0.05) promoting the biomass of shoot and roots, and the chlorophyll content (shown by the SPAD values) in leaves. Among the fertilization treatments, application of 60% bio-organic fertilizer plus 40% chemical fertilizer resulted in the significantly highest yield and best quality of cabbage heads (with increased sugar and vitamin C contents, and less nitrate accumulation, P < 0.05). Moreover, principal component analysis (PCA) demonstrated that the significantly better plant growth effect did not correspond to the variation of soil nutrients. Rather, it may be related to the loaded microbes which were previously reported to be able to promote plant growth via producing phytohormones and activating the local microbiome.[Conclusion] Application of 60% bio-organic fertilizer combined with 40% chemical fertilizer, which allows the roots to develop to the maximum in such a saline ecosystem, is the optimized fertilization regime to cultivate cabbages in saline agriculture in coastal mud flats. Besides, compared to the nutrient load from the fertilizers, the function of the Trichoderma strains was found to be more directly linked to the plant-beneficial effect of this fertilization regime. The biological effect from the applied strains did not significantly rely on the origination of a specific strain. Moreover, the requirement of applying a local saline soil strain to the saline agriculture was not fully addressed here at least not in this study, and thus, needs further investigations.