Silicon photomultipliers with epitaxial quenching resistors(EQR SiPM) are the bulk resistors under each microcell in the epitaxial layer that are used as the quenching resistors. To enhance the photon detection efficiency and solve the problems of lower fill factor and smaller gain for the large dynamic range of EQR SiPM, Novel Device Laboratory (NDL) has changed the size of microcells and newly developed SiPMs with microcell sizes of 15 μm and 7 μm and an active area of 1 mm×1 mm based on its previous work. By changing the size of the microcell, the filling factor of the device is effectively increased, thus, improving the photon detection and gain efficiency. The microcell densities of the 15 μm and 7 μm devices are 4 400/mm2 and 23 200/mm2, respectively, which still maintain a large dynamic range. EQR SiPMs can distinguish at least 13 p.e. and the gain values are 51×105 and 1.1×105 under 5 V overvoltage. Moreover, the peak photon detection efficiencies at a 400 nm wavelength can reach 40% and 34%.