The invention discloses a maximum torque current ratio control method of a five-phase permanent-magnet motor under direct torque control. The maximum torque current ratio control method comprises thesteps of detecting a rotational speed of the motor, comparing a given rotational speed Omega<ref> and a feedback rotational speed Omega<m>, and obtaining reference torque Te-ref by a PI controller; performing conversion matrix on a sampled phase current to obtain currents i<Alpha>, i<Beta>, i<Alpha 3> and i<Beta3> under a primary space Alpha-Beta and a third space Alpha3-Beta3 of a two-phase static coordinate system; calculating voltages u<Alpha>, u<Beta>, u<Alpha3> and u<Beta3> according to a switch signal; inputting u<Alpha>, u<Beta>, u<Alpha3> and u<Beta3> into a magnetic flux torque calculation model to solve flux linkage Psi<s> and torque Te of a motor stator; inputting Psi<Alpha>, Psi<Beta>, i<Alpha> and i<Beta> into a virtual signal module, and performing calculation to obtain compensation flux linkage Delta Psi<s> for allowing the motor to run at an MTPA point; and comparing the reference torque, the flux linkage, the motor torque obtained by calculation and the flux linkage, inputting to a switch table after a hysteresis controller to obtain each phase switch signal. The motor is controlled by the inverter, and MTPA control of the five-phase permanent-magnet motor under direct torque is achieved.