The invention discloses an escapement mechanism of a mechanical watch, which comprises a double disc, a roller jewel, an escapement lever and an escapement wheel, wherein, the roller jewel is fixed onthe double disc and is pressed with a pendulum shaft and a balance wheel as a whole body; the escapement lever comprises an escapement lever body, a lever body, a lever washer and a lever position nail; two arm of the escapement lever body are in a shape of 'L', a lever head of which is fixedly provided with the lever position nail; the lever position nail is fixed on the lever head of the leverbody; the left lever body and the right lever body of the lever body are fixedly provided with an inlet lever and an outlet lever; the escapement wheel and an escapement gear shaft are riveted as a whole body; the escapement lever body, the lever body, the lever washer, and the lever shaft of a lamination escapement lever are directionally pressed as a whole body with a coaxial rotation by the lever position nail. The escapement mechanism of the mechanical watch has the beneficial effects that: the dual positioning of centering and directioning is used for accurately positioning the escapementlever body and the lever body ; the lever washer can effectively prevent the mutual interference of the lever body and the escapement body; the escapement lever with superposition setting reduces plane space occupied by the escapement mechanism, thus being more convenient for the plane arrangement and meeting design requirements on varying specifications.