The X-ray phase analysis without standards is an important quantitative method. The problem of the abnormal state equation lead to the results of composition with large error. The least square simultaneous equations in some cases of combination also have the problem of the abnormal state equation. The least square simultaneous equations method in the quantitative X-ray phase analysis without standards has been proposed, from which the stable solutions can be found. The calculating methods of the stable solutions in different sample number and combination conditions are indicated.