Abstract: The La_0.96Sr_0.04MnO₃/SrNb_0.01Ti_0.99O₃ p-n heterojunction fabricated by the magnetron sputtering technique exhibits excellent rectifying characteristics over the temperature range from 20 to 300 K. From fitting results of the I-V curves,it is found that the electrical transport properties of the heterostructure are mainly affected by the thermal activation effect above 100 K.Moreover,the heterojunction exhibits obvious metal-insulator transition at 170 K,the curve of temperature vs.resistance shows an insulator→metal→insulator transition process.Under a magnetic field of 5 T,the magnetoresistance （MR） of the heterojunction increases from negative to positive with the temperature increasing under forward voltages.And an opposite process occurs under reverse voltages.The largest negative MR is -50. 6%under reverse voltage of -1V at the metal-insulator transition temperature.