As a type of mobile robot, transfer robot has extensive application prospect. Artificial potential field method was studied as an obstacle avoidance algorithm from the perspective of safe obstacle avoidance. Frequent problems such as local minimum and destination unreachable during route planning process of traditional artificial potential field method were analyzed. Through introducing virtual obstacle model, the problem of local minimum was solved, and with respect to the problem of destination unreachable, repulsion model was introduced to rectify the obstacles that led to destination unreachable. The feasibility of this improved algorithm was verified by simulation in MATLAB software.