The present invention discloses general formula I of Temozolomide-8-carboxylate compounds, the process for preparation, pharmaceutical compositions comprising the compounds and the use of the compounds and pharmaceutical compositions for the manufacture of an antitumor medicament. The said pharmaceutical composition comprises one or more general formula I Temozolomide-8-carboxylate compounds as active ingredient, together with conventional pharmaceutical carriers. The composition also comprises one or more pharmaceutically acceptable acidic material, optionally second or tertiary alcohol or ester or ether derivatives thereof. The said pharmaceutical composition can be made into various common formulations, particularly oral formulations as well as topically transdermal patches. The present invention also discloses the application of the compounds and the compositions to treat tumor.
