Construction of ecological security pattern is the key to the construction of ecological security screens and the improvement of wind prevention and sand fixation ability. Northern sand prevention belts are the key ecological function areas in the national ecological security strategy pattern of "two screens and three belts", the main source areas of aeolian sand, and the core areas of desertification control in China. Northern sand prevention belts have special landscape ecological bases such as "fragile substrate, sparse corridors and fragmented patches", so it is not suitable to construct traditional ecological security pattern for ecological connectivity. There is no mature theory and method on how to build appropriate ecological security pattern in the northern sand belts, this paper has carried out some preliminary discussion in this regard. Minqin County, located in the middle of the northern sand prevention belts, was taken as a case study. Based on the diffusion mechanism of sandstorm source, anchoring sandstorm source land, building green sand-blocking key points, connecting sand-blocking corridor and optimizing ecological safety network, the paper proposed a logical paradigm for constructing sand-blocking ecological security pattern of "wind source identification-blocking node-wind corridor-constructing network". Based on the multi-source data of land cover, meteorological stations and soil in Minqin County in 2018, RWEQ model, minimum cumulative resistance model and cost path model were used to identify and analyze the total area of sandstorm source in the study area of 3,136 km², which mainly consists of sandy land and other grassland, and presents a block distribution. There are 43 key points for sand control, including the key ecological nodes with relatively good ecological environment and the key obstacle points with relatively poor ecological environment, which are mainly distributed at the inflection point and crossing point of sand source diffusion path. A total of 41 windbreak sand-fixing corridors, totaling 627.4 km, are connected to the key nodes of sand control and distributed in the north of Hongshagang Town and Donghu Town, perpendicular to the diffusion path of sand source. The ecological security optimization pattern of "7 centers, 36 points and 14 corridors" was constructed from aspects of improving the functions of corridors and nodes, constructing the hierarchy system and ecological connectivity, combined with the actually regional conditions. The results show that the paradigm is helpful to understand the ecological security problems and maintenance mechanism of ecological security in northern sand prevention belts, and can provide a new idea for ecological security pattern construction in other arid areas.