In this work, a new type of silicate K3(Y0.88Yb0.10Ho0.02)Si2O7 phosphor was synthesized by solid state method. The up-conversion photoluminescence and optical thermometry properties of samples were systematically studied. The results show that K3(Y0.88Yb0.10Ho0.02)Si2O7 phosphor exhibits red emission under 980 nm excitation. The main emission peak is located at 665 nm, which is attributed to the 5F5→5I8 transition of Ho3+. The up-conversion mechanism of the phosphor and the photon reaction which may lead to up-conversion were studied by logarithmic transformation of the luminescence intensity and excitation power. It is proved that the up-conversion luminescence process for the (5S4,5F2)→5I8 transition is a three-photon mechanism, and the 5F5→5I8 transition is a two-photon mechanism. The fluorescence intensity ratio of the 5F5/(5F4,5S2) non-thermal coupling energy level of K3(Y0.88Yb0.10Ho0.02)Si2O7 phosphor shows its good optical thermometry potential, and the maximum sensitivity is calculated to be about 0.17 K-1 (423 K).