A modular cutting-teeth bit having controllable specific pressure for drilling includes: a module (1), a modular unit (2), a bit body (3), conventional cutting teeth (4) and a nozzle (5). According to mechanical performance of the rocks in the strata drilled and requirements of drilling well, a combination of shapes, sizes and numbers of the module and the modular unit is optimized; effective abrasion edge length of the cutting unit on a certain portion of the bit is controlled; and a constant specific pressure of the cutting unit of the bit during the drilling process is maintained.