A touch-based method for user authentication includes a training stage and an authentication stage. The training stage includes: generating, by a touch interface, a plurality of training touch parameters; and generating, by a processor, a training heat map according to the plurality of training touch parameters. The authentication stage includes: generating, by the touch interface, a plurality of testing touch parameters; generating, by the processor, a testing heat map according to the plurality of testing touch parameters; comparing, by the processor, the testing heat map with the training heat map to generate an error map; and generating, by the processor, one of pass signal and fail signal according to the error map.