The invention a method for manufacturing a 
polyethylene microporous filter tube for secondary filtering of 
compressed air, which comprises the steps of: A, sieving 
polyethylene powder with a sieving 
machine; B, 
coating silicone oil on the inner wall of an external iron tube mould and the outer wall of an internal iron tube mould for reverse mould 
sintering and assembling a mould body; C, pouring siftage sieved by the sieving 
machine between the inner wall of the external iron tube mould and the outer wall of the internal iron tube mould; D, placing the mould body in a constant temperature furnace, 
sintering for 5-6 hours at 250-300 DEG C; and E, cooling the mould body to 
room temperature and de-moulding. As a novel filtering medium, the 
polyethylene microporous filter tube manufactured by novel materials, with novel technology and processes, has high and stable filtering precision, long service life and easy cleaning and is non-toxic, 
corrosion resisting, temperature resisting at 90 DEG C and can be recycled repeatedly and is an ideal material for various industries to implement high precision gas-
solid separation and oil-
gas separation. In the manufacturing process, the filter core is only sintered to form at one time, thereby reducing the cumbersome multi-step manufacturing means and saving the labor.