<p>An engine oil supply system comprises an oil pan (2) for storing lubricating oil. An oil suction pipe (20) is arranged in the oil pan (2). The oil suction pipe (20) coils in the oil pan (2). At least two oil suction parts (215) are arranged on the oil suction pipe (20), so that at least one oil suction part (215) is under the lubricating oil level no matter where the engine is, thereby ensuring that the lubricating oil can flow into the engine through the oil supply system to lubricate all parts of the engine when the engine is slant or upside down.</p>
