The diesel oil fraction upgrading and pour point reducing process has the mixture of diesel oil material and hydrogen passing through the hydroupgrading reaction region to result in diesel oil with low solidification point through reaction under certain condition. The catalyst in the hydroupgrading reaction region includes at least one kind of bulk phase catalyst comprising complex oxide NixWyOz and oxide MoO3 in the weight ratio 0.1-10 and accounting for 40-100 wt% of total catalyst, and at least one kind of upgrading catalyst containing beta-zeolite. The present invention can lower the solidification point, 95 vol% point temperature and sulfur content of diesel oil, and raise cetane number and oxidation stability under mild condition.