The invention discloses a variable diameter sand control screen which comprises a mandrel connected with an oil pipe, an upper connector, a lower connector, a plurality of split sand control screen sheets and sand blocking steel plates, wherein the upper connector and the lower connector are used for connected with a tool, and the two ends of the mandrel are sleeved with the upper connector and the lower connector correspondingly; each sand blocking steel plate is located between two corresponding sand control screen sheets; and the multiple split sand control screen sheets and the multiple sand blocking steel plates just form a complete circumferential outline and are connected to the upper connector and the lower connector through hinge mechanisms. In the natural state, a gap of a certain size is reserved between every two adjacent sand control screen sheets, and each sand blocking steel plate is located on the inner sides of the two corresponding adjacent sand control screen sheets and inside the corresponding gap in a blocking mode; and in the variable diameter state, the hinge mechanisms expand outwards to support the split sand control screen sheets and the sand blocking steel plate to expand simultaneously in the radial direction, and the multiple split sand control screen sheets and the multiple sand blocking steel plates just form the complete circumferential outline. The problem that sand blocks test pipe column runners and buries packers is solved.