The invention discloses a mechanized rice transplanting and seedling raising method. The method comprises the steps of: step 1) sowing; step 2) setting a covering: and step 3) controlling the height, wherein the sowing step is specifically as follows: a floppy disk is used for sparse-sowing transplanting, and indica hybrid rice with the seed weight of 50-60g is sowed in each seeding tray; the covering is an attached two-layer film, a mulching film is firstly attached to the surface of the sowed seeding tray, then bamboo pieces are arched on the ground, and an arch film is attached to the bamboo pieces; when the mechanized rice transplanting and seedling raising process suffers from a high temperature environment, the covering is specifically an imbricated sunshade net; and the height controlling step is specifically as follows: cutting leaves can be used for controlling the height, and when seedling age exceeds 25 days and the height of the mechanized rice transplanting seedling exceeds 23cm, the seedling leaves are cut off to enable the remained height of the mechanized rice transplanting seedling to be between 14cm and 16cm. The mechanized rice transplanting and seedling raising method, provided by the invention, can reduce the layering phenomenon of the mechanized rice transplanting seedling and dead seedling rate, effectively control the height of the mechanized rice transplanting and obtain mechanized rice transplanting with good high-planting quality.