Catalytic synthesis of di( methylphenyl) methane ( CH3C6H4CH2C6H4CH3, DMPMs) from toluene and formaldehyde were investigated over various solids acids. At 140 degrees C and toluene/ HCHO = 5/ 1, the conversion of HCHO over zeolite ( H beta, H-mordenite, HX, HY and HZSM- 5) is limited, while heteropolyacids ( H3PW12O40, H4SiW12O40 and H3PMo12O40) exhibited higher activity and DMPMs selectivity. The best yield of DMPMs reached 81.5% ( conversion of HCHO nearly 100%). H3PW12O40 could be recovered by simply drying and the recycle- used catalyst remained its activity and structure in five runs.