A trigger assembly has a housing, a trigger, a string holder, a bowstring catch biasing member, a safety pin, a safety lock, a pushing arm, a block, a block biasing member and a string stop. The housing has a mouth. The trigger has a trigger element and an actuating lever combined with the trigger element by dovetailed recess and protrusion. The bowstring catch has a string hook and a leg selectively engaging the hook on the actuating lever. The safety pin is moveably mounted in the housing and is supported on the actuating lever. The safety lock is moveably mounted in the housing and has a push rod. The pushing arm has a protrusion abutting the push rod. The block has a transverse rod selectively engaging the front end of the pushing arm. Accordingly, a trigger assembly with two safety features is provided.