The types of slop roof for PY system are divided like closeing installation, horizontal installation, stair installation, rotating installation. the standard is the horizontal installation type and all types are compared to this. in the case of closing installation type reduce 10.21%, stair installation type reduce 0.24%, rotating installation type reduce 1.06% reduce. the result is produced by simulation program. and under several conditions. in this conditions, a point of the compass is able to be changed. and each values is reduced under 5%. therefore the efficiency is able to be estimated. this study is able to make good result for P.V system on the all conditions. change of roof angle is able to change the efficiency of P.V system but the difference is a little. if this study is concerned to P.V system, good expectation is able to be made.