A measuring method for measuring a physiological parameter via a measuring system comprising a test strip, an auxiliary measuring device and an electronic device having an application program and an analog-to digital converting unit is provided. The measuring method includes steps of coupling the auxiliary measuring device between the test strip and the electronic device to form a loop； the electronic device executing the application program to provide a first analog signal, and transferring the first analog signal to the auxiliary measuring device via the loop； the auxiliary measuring device applying a voltage to the test strip according to the first analog signal, and causing the test strip to generate a second analog signal； the analog-to-digital converting unit converting the second analog signal into a digital signal via the application program； and the application program calculating the digital signal to estimate the physiological parameter.
