In this work, a method for sample preparation of high-purity polyimide was proposed for halogens and sulfur determination by ion chromatography(IC) with conductivity detection and, alternatively, by in ductively coupled plasma mass spectrometry(ICP-MS) A relatively high polyimide mass(600 mg) was completely digested by microwave-induced combustion(MIC) using 20 bar of O2 and 50 mmol L NHOH as absorbing solution.