A polyimide film having a coefficient of thermal expansion at a range of 100 to 350 °C (A) and a coefficient of thermal expansion at a range of 350 to 450 °C (B), wherein A and B satisfying the relation of 0 < B/A < 2, wherein the polyimide film has a positive value of coefficient of thermal expansion at a temperature ranging from 350°C or higher, wherein the polyimide film is prepared by a method comprising: adding polymeric components comprising less than 1 mol of 3,3',4,4'-biphenylcarboxylic dianhydride (s-BPDA) with respect to 1 mol of 4,4'-paraphenylenediamine (pPDA), and an end-capping agent comprising phthalic anhydride (PA) to a polymerization solvent to prepare a polyimide precursor, wherein a molar ratio of 3,3',4,4'-biphenylcarboxylic dianhydride (s-BPDA) and 4,4'-paraphenylenediamine (pPDA) ranges from 0.98:1 to 0.99: 1, and the end-capping agent comprising PA is added in an amount of 0.02 to 0.025 mol based on 1 mol of pPDA; dissolving the polyimide precursor in an organic solvent to obtain a polyimide precursor solution; coating the polyimide precursor solution on a substrate; and bringing the coated polyimide precursor solution into drying and heating to prepare the polyimide film, wherein the polyimide precursor solution is cured during the drying and heating and its final curing temperature is 450°C or higher, wherein the coefficient of thermal expansion is measured according to the method specified in Experimental Example 1 in the description. wherein the polyimide film has a positive value of coefficient of thermal expansion at a temperature ranging from 350°C or higher, wherein the polyimide film is prepared by a method comprising: adding polymeric components comprising less than 1 mol of 3,3',4,4'-biphenylcarboxylic dianhydride (s-BPDA) with respect to 1 mol of 4,4'-paraphenylenediamine (pPDA), and an end-capping agent comprising phthalic anhydride (PA) to a polymerization solvent to prepare a polyimide precursor, wherein a molar ratio of 3,3',4,4'-biphenylcarboxylic dianhydride (s-BPDA) and 4,4'-paraphenylenediamine (pPDA) ranges from 0.98:1 to 0.99: 1, and the end-capping agent comprising PA is added in an amount of 0.02 to 0.025 mol based on 1 mol of pPDA; dissolving the polyimide precursor in an organic solvent to obtain a polyimide precursor solution; coating the polyimide precursor solution on a substrate; and bringing the coated polyimide precursor solution into drying and heating to prepare the polyimide film, wherein the polyimide precursor solution is cured during the drying and heating and its final curing temperature is 450°C or higher, wherein the coefficient of thermal expansion is measured according to the method specified in Experimental Example 1 in the description. adding polymeric components comprising less than 1 mol of 3,3',4,4'-biphenylcarboxylic dianhydride (s-BPDA) with respect to 1 mol of 4,4'-paraphenylenediamine (pPDA), and an end-capping agent comprising phthalic anhydride (PA) to a polymerization solvent to prepare a polyimide precursor, wherein a molar ratio of 3,3',4,4'-biphenylcarboxylic dianhydride (s-BPDA) and 4,4'-paraphenylenediamine (pPDA) ranges from 0.98:1 to 0.99: 1, and the end-capping agent comprising PA is added in an amount of 0.02 to 0.025 mol based on 1 mol of pPDA; dissolving the polyimide precursor in an organic solvent to obtain a polyimide precursor solution; coating the polyimide precursor solution on a substrate; and bringing the coated polyimide precursor solution into drying and heating to prepare the polyimide film, wherein the polyimide precursor solution is cured during the drying and heating and its final curing temperature is 450°C or higher, wherein the coefficient of thermal expansion is measured according to the method specified in Experimental Example 1 in the description. <EOS>