The utility model provides an engine cylinder block and an engine. An upper balance shaft cavity and a lower balance shaft cavity are arranged at the upper part and the lower part of the engine cylinder block respectively; a first hole for mounting the front shaft neck of an upper balance shaft assembly is formed in one end in the upper balance shaft cavity, and a second hole for mounting the middle shaft neck of the upper balance shaft assembly is formed in the middle of the upper balance shaft cavity; a third hole is formed in the other end of the upper balance shaft cavity and used for mounting a U-shaped patch for sealing the upper balance shaft cavity. According to the embodiment of the utility model, a double-balance-shaft structure is adopted; an upper balance shaft is directly connected with the main oil gallery of the cylinder block through two inclined oil holes; a lower balance shaft is connected with the main bearing hole oil gallery of the cylinder block through two inclined oil holes; a chain drive mode is used for driving the two balance shafts to rotate so as to eliminate the first-order reciprocating inertial force and second-order vibration of the engine. Therefore, an ideal damping effect is achieved, the noise of the engine is lowered, the service life of the engine is prolonged, and comfort of passengers is improved.