The invention relates to a locating method for a bulk silicon micromachining process. A method that dual-surface lithography is combined with stepping type lithography is adopted; a stepping type lithography alignment mark of a stepping type lithography machine on a first substrate is found through a dual-surface lithography machine; and then, a second substrate is located by directly using the stepping type lithography machine. The alignment precision of the stepping type lithography machine is equal to the alignment precision of graphs on the surfaces of lower and upper substrates; and thus, the alignment precision of the bulk silicon micromachining process is greatly increased.