Objective To provide the basis for determining the suitable collecting time of safflower. Methods To measure the contents of saflor yellow-A in safflower crude drug from different collecting time in one day by HPLC. Results Only saflor yellow-A has big change. By experimental analyzing samples of different year and region, A bright time collecting in the flok, the content of saflor yellow-A in medicine assured higher. Conclusion A bright time collecting has some scientific basis.