The wormhole morphology is the basis for evaluating the effect of acidizing in carbonate reservoirs. In this paper, the physical properties of the carbonate rock in Dengying Formation of Shehong-Yanting block in Penglai natural gas area are tested. Based on the physical properties of the rock and dual-scale model, the mathematical model of the large-scale multi-component acid corrosion is established. The influence of engineering factors such as acidic fluid viscosity and acidic fluid injection rate on the wormhole expansion is analysed. Based on the principle of the orthogonal experiment, the effect degree of various factors on the wormhole expansion is studied by using the breakthrough pore volume ratio as the evaluation index. It is found that the carbonate rock is mainly composed of ankerite, calcite and a small amount of quartz and clay minerals. The relative content of ankerite, the main mineral component of the rock, is as high as 84.96% to 91.28%. The porosity of the rock is 0.1 ± 0.02, and the rock average permeability is about 5mD. The acidic fluid with high viscosity, low H+ diffusion and low H+ reaction rate is conducive to the main wormhole expansion. Appropriately increasing the acidic fluid injection rate can help increase the main wormhole length, but too large acidic fluid injection rate leads to the expansion of the secondary wormholes, which increases the acidic fluid filtration volume. The influence degree of each factor on the wormhole expansion is as follows: the acidic fluid injection rate > the H+ diffusion coefficient > acidic fluid viscosity. The results lay a foundation for the reservoir acidification research of Dengying Formation in Penglai natural gas area.