In addition to fierce intra-industry competition, chain businesses face many external problems. One problem is that the traditional stand-alone point-of-sale (POS) system has been unable to quickly grasp the operating performance and management of each branch. Another problem is that equipment costs continue to increase with the number of stores. Therefore, the Taiwan government has included cloud computing in its initiative to promote emerging smart industries. In addition, the world is actively investing in the cloud computing industry. Owing to security concerns, however, many domestic enterprises are reluctant to adopt cloud-based services. Secure cloud service applications must be developed to maintain and expand market share. We implement a Cloud Web POS 365 Platform with a multifactor and threshold authentication. Then, we use the required and threshold parameters to generate a key for encryption/decryption. Finally, we deconstruct a ciphertext to partial ciphertext segments and store it in each partial ciphertext database. Hence, this study contains 4 security levels. First, users need the required parameters including positioning information; when the machine is not in the set range, it cannot be used. Second, users need the threshold parameters stored in a radio frequency identification card and obtain enough card information to log into the system. Those parameters above are generating the encryption/decryption key. Third, we use a symmetric encryption module to encrypt data. Fourth, we design a deconstruction/reconstruction module to store partial ciphertext segments separately. Therefore, the proposed scheme is more secure than other cloud web POS systems. Moreover, its web-based architecture enables easy implementation in any platform. As a result, the proposed scheme would be effective for increasing the operating efficiency of chain businesses.