The invention discloses a rotary displacement type rotating wheel vortex mechanism (1) for a fluid machine and an engine. The rotating wheel vortex mechanism (1) is divided into an inner rotating wheel vortex mechanism (2) and an outer rotating wheel vortex mechanism (3) according to structural characteristics, wherein concave wheel rotors (6) of the inner rotating wheel vortex mechanism (2) are meshed for dynamic sealing rotation in an inner rotating wheel cylinder sleeve (4); convex wheel pistons (8) are arranged on the concave wheel rotors (6); the convex wheel pistons (8) and the concave wheel rotors (6) rotate together and automatically rotate in the same direction; fluid in a vortex chamber (16) between the two convex wheel pistons (8) is continuously sucked and discharged under the action of a separator (15); convex wheel rotors (37) of the outer rotating wheel vortex mechanism (3) are meshed for dynamic sealing rotation in an outer rotating wheel cylinder sleeve (36); concave wheel pistons (38) are fixed on the outer rotating wheel cylinder sleeve (36) and are meshed with the convex wheel rotors (37) for dynamic sealing reverse rotation; the fluid in the vortex chamber (16) between two convex wheels (47) on the convex wheel rotors (37) is continuously sucked and discharged under the action of the concave wheel pistons (38).