Due to its invisibility feature, pressure force is useful to enhance the security of authentication, especially preventing shoulder surfing. However, it is challenging to memorize a pressure-based password. This paper presents a pressure-based authentication system with personalizing the detection of pressure force, which concretizes a pressure-based password as a decimal number to reduce the effort of memorization, improve the accuracy, and enhance the security. We conducted two user studies to compare the four-pin password with our pressure-based password regarding their usability performance and security evaluation. The results of the first study indicated that the pressure-based password is more secure, but the four-pin password is faster and has higher subjective satisfaction. We have conducted a second study that asked participants to use the pressure-based password once every day for 10 continuous days. The second study revealed that both the completion time and subjective satisfaction of the pressure-based password were significantly improved.