A characteristics that has a portable precooling apparatus of forced draft and pressure differential ventilation dual mode simultaneously, and it has, and cool time is short, the cooling capacity is strong, loading and unloading are convenient, equipment is miniaturized is provided. Precooling apparatus possesses: the two compression refrigeration compressors of duplex, frequency conversion control, accurate temperature control, fan (2), goods stock room (A, B), ventilation duct (10), freight track (8), container (5), deep bead (3), air distributor (7) in an organic whole, deep bead (3) will ventilate the route and separate for a plurality of regions, the route that should ventilate be through high negative -pressure air fan (2) air supply through evaporimeter (1), blow to stock room (A, B) through air supply air distributor (7) air outlet, then pass through the return air inlet by high negative -pressure air fan (2) with the high -temperature gas in the stock room and inhale, form gas circulation cooling route. Deep bead (3) can fall into the space of stock room forced draft district and pressure differential ventilation district.