The crude oils from the Mesozoic-Cenozoic reservoirs in the western Turpan-Hami Basin are mainly high-wax condensate or high-gravity oil (or light crude oil), with lower density, viscosity, middle to high paraffin content and higher content of high-molecular weight n-alkane (nC 35~nC 87). The paraffin contents of crude oil samples range from 5.5% to 22.1%. The origins of high-wax condensate and high-gravity oil are different from those of normal high-wax crude or condensate. The reason of the formation of high-wax condensates or high-gravity oils in the Mesozoic-Cenozoic reservoirs in the region of interest, which derive from the Jurassic mudstone and/or coalbeds, attributes to the constituents of organic macerals in source rocks and maturity of organic matter. The organic macerals in mudstone and coalbed source rocks in this region include mainly vitrinite and exinite consisting mainly of cutinite and suberinite, with the conditions of the formation of high-wax crude oil and condensate or high-gravity oil. The high-molecular weight n-alkanes and the condensates were generated at the same temperature because the activation energy of the vitrinite maceral and some exinite macerals in coalbed source are close.