The invention discloses a manufacturing process for a step circuit of a PCB (Printed Circuit Board). According to the manufacturing process, different film patterns are adopted twice for manufacturing the circuit, during the primary film pattern circuit manufacture, a positive film circuit pattern is adopted, compensation is carried out a film substrate circuit at different positions according to copper thickness so as to manufacture a special circuit, and sunk copper plate electrification is carried out on the special circuit, so that the copper thickness meets the requirement; then board grinding is carried out by a twice board grinding mode so as to reduce the copper thickness difference of step positions; a dry film is enabled to be fully combined with the step positions by virtue of a film attaching and air compressing mode; and finally, normal circuit pattern manufacturing is carried out by utilizing a high-precision LDI (Laser Direct Imaging) exposure machine. Compared with the prior art, the manufacturing process for the step circuit can be used for eliminating the defects of open circuit at the position of the step circuit, notches, large deckle edges, serious lateral erosion, halfway etching and poor quality of thin lines and the like existing in the step circuit manufacturing process, improving the production efficiency and the production quality, quickening the production schedule and lowering the production cost.