The invention discloses an order picking method and system. The method includes the steps that firstly, an order is selected, order parameters and commodity parameters are acquired, and sorting site parameters of each sorting site in a warehouse and lot maximum power parameters are determined; secondly, the number of lots is calculated; thirdly, the coordinates of all commodities in the order are calculated in each sorting site coordinate system; fourthly, all lot orders are acquired in the sorting site coordinate system; fifthly, the sum of distances between all lot order commodities in each lot order and the original point of the sorting site coordinate system is calculated; sixthly, the minimum value of the calculated sum of distances and the corresponding lot order are acquired; seventhly, the original point of the sorting site coordinate system is regarded as a starting point, and the connecting lines of the original point and all the lot order commodities in the lot order are regarded as order picking paths. By means of the order picking method and system, the order picking paths of all the commodities in the order can be calculated according to the storage positions of all the commodities in the warehouse, cost can be reduced as much as possible, and delivery efficiency can be improved.