Abstract: 【 Objective 】 This study aims to examine the effects of application time of Flumetralin and Mepiquat chloride on plant type and economic characters of cotton, In order to screen out the optimal time for chemical capping and pre-regulation and shaping of cotton. 【 Methods 】 The split-plot experiment design was carried out in this experiment to determine the plant height, leaf branch length, fruit branch length, internode length, boll number, boll weight, single boll weight, yield and fiber quality index of cotton capping period as the main plot, cotton with different time before capping as secondary zone and artificial topping as control. 【 Results 】 Flumetralin and Mepiquat chloride were administered twice in cotton field for cotton regulation and capping. The plant height and leaf branch growth of cotton chemical capping were lower than those of artificial topping. The longer the two-period application period of plant growth regulators mixed with Flumetralin and Mepiquat chloride, the shorter the cotton plant height growth. The distance between main stem nodes of cotton inverted one, inverted two, and inverted three was significantly shorter than that of the control (P <0.05), and the length of the fruit branches of inverted one, inverted two, and inverted three was 61.57% -70.57% shorter than the control. The number of cotton bolls in different parts of cotton was as follows: lower boll > middle boll > top boll, and it was mainly concentrated in the lower part of cotton. With the shortening of the interval between the two treatments, the number of bolls per plant and the weight of single boll increased, while the single boll weight of cotton capped on July 15 decreased, but there were no significant difference between each treatment and control (CK0-5, CK0-10, CK0-15)(P>0.05). 【 Conclusion 】 The interval of two applications also had certain influence on cotton fiber quality index. According to weight of seed and lint yield of cotton, the plant growth regulators mixed with Flumetralin and Mepiquat chloride sprayed twice on June 30th and July 10th can cause cotton to cap itself and help the formation of higher light efficiency groups.