Total reflection X-ray fluorescence spectroscopy （TXRF） and X-ray photo-electron spectroscopy （XPS） have been used to investigate residual impurities and oxides on polished InAs substrate surface wet cleaned by different solution combination. Metal impurities Si， K and Ca are routinely detected on the cleaned InAs surface and their concentration change with the variation of solution combination. A large quantity of particles （80 nm size） is measured on the InAs substrate surface with higher residual impurity concentration. An effective wet chemical cleaning procedure is presented to prepare InAs substrate surface with less residual impurity， small particle quantity and thin oxide layer， which are beneficial to high quality epitaxial growth.