Low-altitude intelligent network is an instrumental infrastructure for the outgrowth of low-altitude economy. However， the safety control of the unmanned aerial vehicles （UAVs） presented in such complex system faces multiple security challenges such as airspace security， data security， and spectrum security. To address these three issues simultaneously， a blockchain-based three-sided collaborative regulatory architecture， with the use of both “on-chain” and “off-chain” information， is proposed. The “on-chain” contains identity and registration information of UAVs， while the “off-chain” contains automatic dependent surveillance-broadcast （ADS-B） information and spectrum information. To solve the problem of cross-domain authentication， an effective signature algorithm is developed， which is based on the ADS-B information and certificateless signature. Furthermore， due to the lack of error correction mechanism in the ADS-B protocol， errors are easily incurred by channel noise and interference during the transmission of the ADS-B information. Consequently， the hash verification may fail. In order to alleviate such signature failure， a cross-layer signature algorithm based on error correction code is designed for correcting errors. The proposed blockchain-based three-sided collaborative regulatory platform has been well experimented over the Yangtze River low-altitude demonstration pilot zone and achieved great success.