The present invention relates to a process for producing a binder-free ZSM-5 zeolite in small crystal size. The invention is primarily used for solving the problems in the practical application, e.g., the zeolite powder is difficult to be recovered and easily inactivates and aggregates, and the addition of the binder in the shaping process will result in the reduction of effective surface areas and introduce the diffusional limitation. Said problems are better solved in the present invention by using diatomite or silica aerogel as the main starting material, adding a seed crystal orienting agent, a silica sol and sodium silicate for kneading and shaping, and then converting to integrative ZSM-5 in small crystal size by vapor-solid phase crystallization with organic amine and water vapor. Said process can be used in the industrial preparation of ZSM-5 molecular sieve catalyst in small crystal size.