A novel Interference Cancellation algorithm based on pressure pulse width (PPW) signal is presented, in order to ensure the high reliability of measurement results in pulse detection system with capacitive sensors. There is an output function of pulse width as the system analysis model, which has the corresponding relationship with pulse pressure. The analysis is conducted by using first order difference algorithm of discrete sequence, which can reveal the change rate of pulse signals. And the bubbling up sorting method is used for acquiring the pulse cycle automatically. The experimental comparison and analyses indicate that the sensor with this algorithm maintains a more effective way on filtering un-orderly signal, especially enhancing the reliability of dynamic pulse detection.