An experiment on six Venturi injectors in Beijing was carried out. Based on theory studies, the differences of fertilization performance including fertilizer suction amount, the inlet discharge, the critical discharge and the critical pressure were analyzed and the regression models were built. It showed that the fertilizer suction amount and the inlet discharge were affected by the inlet and the outlet pressure directly. Domestic brands YR and RF were sensitive to the pressure fluctuation, while foreign models NF and AD could adjust to work environment better. The critical pressure of brands NF and AD-1 were very low, thus these models have a long working range. In contrast, the critical pressure of the models RF and YR got to a half of the inlet pressure for a normal fertilization, and this means they have a short working range. 