The invention discloses a production system of modified heavy calcium carbonate dry powder. Compared with the prior art, the system includes a batching apparatus, a first buffer tank, a wet mill, a first screening device, a hydraulic cyclone separation system, a second screening device, a second buffer device, a centrifugal dehydrator, a drying feedback stirrer, a drying beater, a drying and beating dust removal device, a comprehensive tank, an acid-coating and modification machine, an acid-coating and modification dust removal device, a first acid-coating cloth bag filter, a second acid-coating cloth bag filter, a modified product storage tank and a modified product packaging machine. The second screening device is connected with the hydraulic cyclone separation system, the centrifugal dehydrator is connected with the second buffer device, the comprehensive tank is connected with the drying and beating dust removal device and the drying feedback stirrer, and the acid-coating and modification machine is connected with the comprehensive tank. According to the scheme, compared with the prior art, the produced modified calcium carbonate powder is excellent in quality, the processing fluidity and other comprehensive quality of the calcium carbonate material are easily improved, the production stability of gas-permeable membranes and the product quality are improved.