Abstract: The rules of variation of exhaust gas pressure for turbocharged multi-cylinder diesel engines are studied. Gas pressure at the exhaust port and cylinder pressure of the first cylinder are measured synchronously in the exhaust stroke under various operating conditions using instantaneous pressure sensor and the combustion analyzer on a V-type turbocharged eight-cylinder diesel engine. The measured results indicated that the rule of variation of exhaust gas pressure were similar under the same engine speed. Along with increased loads, the fluctuant range of exhaust gas pressure increased. Under different engine speeds, the phase of wave crest and wave trough in the exhaust pressure curve postponed backwards along with increasing engine speed. Under some operating conditions, pressures in the cylinder are higher than gas pressures in the exhaust port on the exhaust period. Under some other operating conditions, pressures in the cylinder are smaller than gas pressures in the exhaust port.