The invention discloses a micro-
accelerometer and a preparation method thereof, belonging to the technical field of 
processing micro 
inertia devices. The micro-
accelerometer is arranged on a 
package substrate which is formed by stacking an upper 
surface plate, a lower 
surface plate and a plurality of middle substrates, wherein a 
signal detection circuit of the micro-
accelerometer is attached on the upper 
surface plate; a sensitive element of the micro-accelerometer is embedded in the middle substrates, i.e. the middle substrates with cavities form a frame of the sensitive element; a flexible hanger and a sensitive 
mass block of the sensitive element are arranged in the cavities, and one end of the flexible hanger is connected with the sensitive element, while the other end is fixed on the frame; 
metal electrodes are respectively sputtered on the sensitive 
mass block and the surface of the frame corresponding to the sensitive 
mass block so as to form a flat plate sensitive 
capacitor, or a 
metal piezoresistive thick-film pattern is deposited at a connecting part of the flexible hanger and the inner side surface of the frame so as to form a 
metal piezoresistive 
strain gauge. The micro-accelerometer has high sensitivity and high-
temperature resistance and can be fused into a whole with a 
system level 
package substrate, thus the micro-accelerometer has low 
processing difficulty and cost.