A positioning method and device based on multi-sensor fusion are provided and relates to object positioning field. The method includes obtaining sensor data collected by various sensors on a movable object in real time; temporally and spatially synchronizing sensor data collected by the sensors to form various temporally and spatially synchronized sensor data; performing data preprocessing and correlation on the temporally and spatially synchronized sensor data to form to-be-jointly-optimized sensor data; obtaining state information at each time point before a current time point in a preset sliding window; and determining a current pose state of the movable object by performing a joint optimization according to the to-be-jointly-optimized sensor data and the state information at each time point before the current time point in the sliding window. The movable object can be accurately positioned in scenarios where GPS signals are lost, jumping exists, or LiDAR observation is degraded seriously.