Traditional network data security sharing system ignores that many people share data simultaneously, which leads to poor real-time performance. Therefore, the authors designed a network data security sharing system based on blockchain technology. In the hardware design, the PCI encryption card is used to encode the data. The microprocessor is used to access the system’s external equipment, and DDR-SDRAM dynamic storage area and NAND flash static memory are used as network data. In the software section of the system, a secure transmission mechanism is established. The cp-abe method is used to encrypt the network shared data, and the multi-person digital envelope technology is used to share the data. These two methods contribute to the design of the network data security sharing system. In the experiment, eight users share the data. The system login response time, key distribution time, data encryption time, and key update time are taken as the experimental objects. Experimental results show that the system response time, key distribution time, data encryption time, and key update time of the system are shorter than those of the comparison method.