Abstract: Inner shell photo-ionization scheme is one of ways to induce population inver-sions; How to obtain X-ray laser which wavelengths lie near the“water window”using middlepower laser facility is interesting in nowadays.In this paper we introduce the experimentalinvestigations to get population inversions under the condition of bi- target coupling by innershell photo-ionization scheme.The contents include experimental principle,target type selec-tion. x- ray intensity measurement of pumping target,spectral diagnosis of working target andso on. At finally the experiment discussion and results indicate that bi- target coupling schemeonly can form a few number of population inversions under the condition of these experiments.