A quantum metrology protocol for continuous force sensing is developed beyond the quantum standard limit on performing a coherent quantum noise cancellation (CQNC) strategy in an optomechanical system, that consists of two optical modes with non-identical frequencies and a mechanical mode. In particular, an ultrasensitive susceptibility around the mechanical-mode frequency is solely achieved with driving the higher-frequency optical mode and probing the lower-frequency one. More importantly, this asymmetrical and unique treatment allows the ancillary optical mode to constitute an effective coherent channel for implementing the CQNC strategy, when the ancillary mode is set to be near-resonant with the probe mode to avoid the disturbance from the driven mode. The ancillary mode then acts as a negative-frequency mechanical oscillator to offset the backaction noise arising from both radiation-pressure and driving. Under the condition of strong driving and strong coupling, the measurement sensitivity as well as the signal-to-noise ratio in our optomechanicalsensing scheme is therefore found to be significantly enhanced by about two orders in magnitude, comparing to that without noise cancellation. In addition, our scheme can be practiced in a tripartite optomechanical setup with a membrane in the middle and a twisted-cavity-based weak-torque detector.