In this paper, we demonstrate a top-illuminated InGaAs pin photodetector grown on InP substrate. The fabrication, measurement and characterization of this photodetector are discussed in this paper. Low dark current densities of 1.37×10-5 A/cm2 at 0 and 93×10-5 A/cm2 at a reverse bias of 5 V are achieved. At a wavelength of 1.55 μm, the photodetectors have a responsivity of 0.61 A/W without antireflection coating, a linear photoresponse up to 28 mW optical power and a maximum linear photocurrent of 17 mA at -3 V. The measured 3 dB bandwidth of a 22 μm-diameter photodetector is 17.5 GHz.