The utility model discloses an intelligence fertilizer injection unit that waters belongs to gardens and plants the maintenance field, aims at solving the current gardens problem that fertilization manual operation is complicated of watering, including liquid storage tank (1), sprinkling machine (3) the liquid storage tank lead to pipe and sprinkling machine connection, be equipped with measuring pump (4) on the water pipe, liquid storage tank (1) be connected with inlet tube (2), the measuring pump be connected with central processing unit (5), be connected with humidity transducer (6) at the soil the inside with central processing unit.