Northeast China is the main spring maize production base of China. It is of great significance to stabilize and keep on raising yield of the crop in this region in guaranteeing development of the maize-related industry and food security in China. The technique of blending controlled release N fertilizer (CRN) with common urea once for ado can be used in fertilization of maize not only to regulate the supply of available and slowly available N so as to meet the demand of the crop for N during its growing season, but also to reduce fertilizer and labor input cost to increase economic profit. However, so far little has been reported on researches on such techniques for spring maize in Northeast China, and is known of effects of the use and proper ratio of such a blend. Therefore, 3-year-long multi-site field experiments were carried out to explore effects of the blending on growth at the jointing stage, grain yield and yield composition at maturity, N use efficiency, and economic profit of spring maize relative to blending ratio and environment, so as to define effect of the use and optimal ratio of the blend by determining relationships of ratio of the blend with grain yield, partial factor productivity of N fertilizer (PFPN), and fertilization profit of spring maize. The 3-year-long (2009 to 2011) multi-site field experiments consisted of nine experiments in the major maize production area in Central Jilin province and were designed to have five fertilization treatments, i.e. Treatment I (No N fertilizer); Treatment II (100% common urea); Treatment III (15% CRN and 85% common urea); Treatment IV (30% CRN and 70% common urea), and Treatment V (45% CRN and 55% common urea). Total N fertilization rate was kept consistent for all the treatments, being 185 kg hm^-2 during the growing season. The results showed that a higher proportion of CRN in the blend improved spring maize in plant height and leaves in number and SPAD at the jointing stage, but did not affect much stem diameter. Summary of the nine experiments indicated that both grain yield and fertilization profit of spring maize increased significantly with increasing blending ratio of CRN, and reached the highest, 10.12 t hm^-2 and 5 071 yuan hm^-2, respectively, in Treatment IV, being 0.98 t hm^-2 (10.8%) and 1 639 Yuan hm^-2 (47.8%) higher than that in Treatment II, respectively. The effect of higher blending ratio of CRN increasing grain yield of spring maize was mainly attributed to the significantly increased number of kernels per ear at the maturing stage, and also to the increased ear number. A rising proportion of CRN in the blend increased significantly PFPN of spring maize, but reduced significantly contribution rate of soil N (CRSN), till it reached 30%. In all the nine sites of the experiment, significant quadratic relationships were observed of blending ratio of CRN with grain yield, PFPN, and fertilization profit of spring maize. For the above three parameters, the optimal blending ratio of CRN for spring maize was figured out to be 35.1%, 35.2%, and 33.7%, respectively. Obviously, blending of CRN with common urea in fertilization is conducive to growth of spring maize, higher yield of grains, higher N use efficiency, and higher economic benefit. Based on all the findings in the experiment, the optimal blending ratio of CRN for spring maize production in Northeast China is worked out to be 30%~35%.