A direct-type backlight module and a manufacturing method thereof are provided. The direct-type backlight module includes: a rear plate and a backlight source installed therein. The backlight source includes a LED light bar including LEDs. The LEDs have a phosphor layer disposed thereon. The phosphor layer and the LEDs have a colloid material layer sandwiched therebetween for thermal isolation. The present invention disposes the colloid material layer so as to avoid heat generated by the LEDs to be directly transferred to the phosphor layer to cause efficiency reduction, meanwhile there is no need of a large amount of phosphor layer to fabricate a large-sized film sheet and thus the material usage of the phosphor layer is reduced. The present invention can effectively use the phosphor layer to improve color saturation of display while ensuring the efficient use of LED brightness and the life span by the colloid material layer.