A high sensitivity magnetic field and temperature sensing structure based on photonic crystal fiber(PCF) is designed. Magnetic liquid is filled in an air hole of PCF cladding to form the directional coupling structure. The magnetic field and temperature variations of the structure are measured. The characteristics of the sensor are studied simulatively by using a full vector finite element method (FEM). The results show that the sensing structure can realize measurement within the magnetic field range of 100~250 Oe（1 Oe=79.58 A/m） and the temperature range of 10~60 ℃. The magnetic field and temperature sensitivities can reach 1.10 nm/Oe and -3.86 nm/℃ within the range.