A synchronous localization and mapping method for vision-
inertia-
laser fusion mainly relates to the technical fields of multi-
sensor fusion, SLAM and the like. In order to solve a problem that single sensor SLAM has low precision and is easy to lose in localization and mapping, the invention provides a robust high precision vision, 
inertia, 
laser radar fusion SLAM 
system. A tightly-coupled visual 
inertia odometer is further optimized through 
laser radar scanning and matching so as to obtain a more accurate localization result. And when a camera or a laser 
radar degenerates, and a visual inertia module or a scanning and matching module can not work normally, a 
system automatically integrates remaining workable modules to maintain stable 
pose estimation. In order to remove cumulative errors, 
loopback detection based on an appearance and neighboring matching based on 
point cloud are added, and then six-degree-of-freedom 
pose optimization is performed to maintain 
global consistency. In the invention, robust high-precision localization and mapping effects can be obtained.