The invention provides a manufacturing method of tanned shrunk grain top layer leather. In the method, crust leather is successively subjected to following processes: degreasing, re-tanning, neutralization, filling, dyeing, fat-liquoring, stacking, vibration-softening, leather grinding, painting-decoration and roll-burnishing. In the re-tanning process, by means of addition of sodium carbonate, the pH value of liquid in a drum machine is regulated to be 8-10 and meanwhile the temperature of the liquid is adjusted to be 33-35 DEG C, and then the crust leather is added with a shrunk grain agent to generate patterns on the crust leather, and finally when the processes are finished, the liquid in the drum machine is drained completely. In the invention, the shrunk grain agent is added at special pH value and temperature for generate bull-shoulder pattern on the crust leather, so that the tanned shrunk grain top layer leather is unique in appearance and is wider in available range when compared with a tanned leather prepared through a conventional technology. Meanwhile, by means of addition of a tannin extract in a special manner and at a special proportion during the filling process, the bull-shoulder pattern on the crust leather can be shaped to form a pattern shrinking effect.