The invention relates to a modeling method for a compound parabolic concentrator (CPC) for a linear Fresnel light condensing and heat collecting system on the basis of matlab. The modeling method comprises the following steps: 1, determining the maximum receiving half angle theta c of the CPC; 2, using an outer diameter circle of a metal inner pipe of a vacuum heat collecting tube as a base circle of an involute; 3, rotating the involute by an angle alpha by using a circle center O as the center, so that a point C on the involute, which meets the condition that t=t0, is positioned on a center shaft of the CPC and the distance between the point C and the metal inner tube of the heat collecting tube is the sum of the distance between the point and a glass outer tube of the heat collecting tube and the distance between the glass outer tube and the metal inner tube of the heat collecting tube; 4, using a point on the involute, which meets the condition (refer to the specification), as a junction point of an involute CFB and a parabola A; 5, rotating the parabola by an angle theta c around the vertex of the parabola to enable the parabola to pass through a left junction point FB and using a right junction point FA as a focus to obtain a parabolic equation; 6, carrying out simulating calculation on a relation of a convergence rate and an intercepting ratio of the CPC by utilizing a ray tracing method, and selecting the suitable intercepting ratio.