The invention discloses a high-precision flow field solving method for triangularized grids with a large length-width ratio, and the method comprises the steps: A, generating an unstructured network,and enabling grid units in the unstructured network to be triangular grids; B, initializing an unstructured network, and reading parameters of the unstructured network; C, calculating an area weighting center of each grid unit in the unstructured network; D, replacing the geometric center of each grid unit with a corresponding area weighting center, and reconstructing each grid unit; step E, constructing a space term based on the reconstructed unit variable and derivative information thereof; and step F, calculating a flow field by using an integral solver based on the space item constructed in the step E. According to the method, high-order precision of flow field solving can be guaranteed, calculation errors are reduced, the solving accuracy of the flow field is effectively improved, unification of grid generation automation and numerical simulation precision on the triangularized grid with the large length-width ratio is preliminarily achieved, and numerical expression of a solver is improved.