The present invention provides a safety device, an elevator safety system and an elevator system. The elevator safety system comprises the safety device which comprises a shell having a vertical passage for elevator guide rails to pass through, the safety device further comprises a first brake block on a first side of the vertical passage, and a second brake block on a second opposite side of the vertical passage; and a safety device carrier for supporting the safety device and fixedly connected to an elevator car; wherein the shell of the safety device is obliquely and movably mounted on the safety device carrier.