| Container slot assignment, a preplanning procedure for container stowage, is to allocate container boxes into certaion slots. However, the attributes for each box are not completely known in advance, most yard operators assign the slots via experience which often causes inefficient usage of slot capacities with unnecessary "restowage" moving, and as a result an increase in operation cost. This paper attempts to develop several stacking strategies and compare their operation efficiency. The containers are divided into two categories--attributes which are known in advance and which are unknown. Container slot assignmetn utilizes such equipment as straddle carrier, forklift, and transtainer, and the operation time is composed of three parts--equipment moving, loading/unloading, and restowage time. By comparing the average operation time for various stacking strategies we find that equipment moving time has little affect on strategy rankings; while restowage time is the key factor dominating the rankings for stacking strategies.