Abstract: According to the issues of the quality of feeding raw coal continually deterioration,the X6042M Jig aged seriously in Fenghuangshan coal preparation plant,caused the processing capacity and separation effect decreased,the original jig was replaced by X6033M Jig,and modified its body,air valve system and automatic discharging device. After the technology improvement,the jig is running stability,the separation precision and efficiency are both significantly increased,and the accident rates is significantly lower. The technology improvement achieves the desired effect.