Polyethylene and preparation method thereof

A polyethylene, of which

• a melt index according to (ASTM D 1238 measured at 190° C. under loaded of 2.16 kg is 15 g/10 min to 40 g/10 min,
• a melt flow rate ratio (MFRR) of MI5/MI2.16 is 2.3 to 2.7,
• an integral value in a region where Log Mw is 3.0 or less in a GPC curve, wherein an x-axis is the log Mw and a y-axis is dw/d log Mw, is 0.8% to 1.8% of a total integral value, and
• a content of a linear hydrocarbon having 3 to 32 carbon atoms based on 1 g of the polyethylene is 600 ppm or less, when a peak area of the linear hydrocarbon having 3 to 32 carbon atoms is converted into a ratio with respect to a peak area of the polyethylene in a GC-FID graph obtained through gas chromatography/flame ionization detector analysis using GC-FID, Inlet, Detector temperature at 300° C., a residence time of 20 minutes.