The invention discloses a negative pressure deodorization system. The negative pressure deodorization system comprises a cabinet, and an inner cavity of the cabinet is partitioned into an upper cavity and a lower cavity through a partition plate. The partition plate is provided with an air guide port for making the upper cavity and the lower cavity communicated. The side edge of the cabinet is provided with an air outlet communicated with the upper cavity and is further provided with an air inlet communicated with the lower cavity. In the lower cavity, a fan, a microorganism attachment box and a dehydration layer are arranged from the air inlet to the interior in sequence. In the upper cavity, a fan, an activated carbon filtration layer and a high-energy ion tube are arranged from the air outlet to the interior in sequence. The air guide port is located between the high-energy ion tube and the dehydration layer. A bottom box is arranged at the bottom of the cabinet. A circulation box is arranged on the partition plate. The upper end of the microorganism attachment box is communicated with the circulation box, and the bottom end of the microorganism attachment box is communicated with the bottom box. A water pump is arranged in the circulation box and connected with sprayers through pulse electronic valves. The sprayers are evenly arranged at the upper end of the microorganism attachment box. The water pump is communicated with the bottom box through a liquid suction tube. A microbial deodorizer is placed in the bottom box. The negative pressure deodorization system is good in deodorization and sterilization effect, capable of preventing secondary pollution and convenient to install and use.