The organic-inorganic latex particles with sulfonic acid groups and core-shell structure are successfully obtained and then are heated to fabricate the self-crosslinked organic-inorganic nanocomposite membranes. Fourier transform infrared (FTIR) spectra confirm the chemical structure of membranes. The effects of inorganic component on the performances of nanocomposite membranes are investigated extensively. TGA analyses show that the membrane materials possess excellent thermal stability and 5% weight loss temperature increase with increasing SiO2 content. Solvent absorption measurement suggests the membranes are less permeable to methanol than water. The obtained membranes show conductivity values above 10(-2) S cm(-1). More importantly, all the membrane materials exhibit more excellent methanol barrier and higher selectivity compared with Nafion 117, demonstrating that those membranes could be a potential candidate as proton exchange membranes for future direct methanol fuel cells.