【Objective】Potassium is a main nutrient element that affects cotton yield and fiber quality. Repeated application of potassium fertilizer can increase cotton yield, but topdressing not only causes mechanical damage to the crop, but also increases labor cost, thus reducing cotton planting benefits. Mepiquat chloride (MC) is a kind of plant growth regulator characterized by low toxicity and water solubility. It is now widely used in cotton planting countries all over the world to inhibit vegetative growth of the plant and hence to eliminate the traditional labor-costing pruning operations. However, so far little is known about whether MC could increase cotton yield when it is applied into the cotton fields. Therefore, the objective of this study is to investigate effects of coated potassium chloride containing MC on cotton yield, economic benefit and balance of soil potassium.【Method】A field experiment was initiated in 2018 with five treatments different in potassium application pattern and three replicates for each treatment, i.e. Treatment CRKMC (basal application of 180 kg·hm^-2 coated potassium chloride containing mepiquat chloride); Treatment 70% CRKMC (reduced potassium dosage (126 kg·hm^-2) or 70% of CRKMC); Treatment CRK (basal application of 180 kg·hm^-2 common coated potassium chloride); Treatment KCl (split application of 180 kg·hm^-2 ordinary potassium chloride, 60% basal and 40% topdressing at the first bloom stage); and CK (no potassium fertilizer used), and in addition foliar spraying of MC was performed three times on each of the latter three treatments.【Result】Treatment CRKMC and CRK increased cotton yield by 8.81% and 9.36%, and economic benefit of the crop by 15.53% and 12.86%, respectively, while Treatment 70%CRKMC increased cotton yield by 6.53% and net income by 13.64%, respectively as compared with Treatment KCl. Treatment CRKMC inhibited cotton plant height before the full-bloom stage, but increased plant height, stem diameter and chlorophyll value at later stages (from the full-bloom stage to maturity stage), and plant biomass by 18.56%~24.98%, as compared with Treatment KCl, enhanced potassium uptake, and also improved apparent K use efficency by 25.06%~38.83%. Release of Potassium and MC in the CRKMC exhibited a trend of “slow – fast – leveling off” in the soil, and peaked during the period between the full bloom stage and the initial boll-opening stage, which significantly increased the content of available potassium in the soil after the squaring stage.【Conclusion】Therefore, application of CRKMC into soil can reasonably regulate the growth potential indices of cotton and meet the demand of cotton for potassium. The application of CRKMC 30% less in potassium dosage can still improve economic benefits of the crop and potassium use efficiency. So CRKMC can realize integrated coordination of MC and K under the same temporal/spatial conditions, which helps reduce fertilization rate, improve crop yield and simplify crop management.