The invention provides a protective device for chain jump and chain breakage of a shallow slot trigger. A chain is disposed respectively on two sides of the shallow slot trigger. The shallow slot trigger comprises a head wheel, a supporting roller and a tail wheel. Each chain extends from the head wheel, passes through the supporting roller, and reaches the tail wheel. A fixing shaft is installed at the position of the head wheel, and a shaft sleeve capable of rotating freely around the fixing shaft is installed on the fixing shaft. The protective device for chain jump and chain breakage comprises a feeler lever and a monitoring system. One end of the feeler lever is fixed with the shaft sleeve, and the other end of the feeler lever abuts against the chain. The monitoring system comprises two approach switches which are connected in series, and each approach switch is disposed beside the fixing shaft of each of the two sides of the shallow slot trigger. The protective device for chain jump and chain breakage is simple to manufacture, sensitive and reliable to use, small in daily maintenance amount and convenient to overhaul.