PURPOSE: To obtain more valuable aromatics, preferably 6-8C aromatic hydrocarbons and olefins, particularly 2-4C olefins at the same time by converting paraffins of ≥5C with the catalyst consisting of ZMS-5 having a relatively low α-value.

CONSTITUTION: At least 90 wt.% of paraffin in a hydrocarbon feedstock (for example coker gasoline, FCC gasoline, etc.), contg. at least 75 wt.% of the mixture of at least two kinds of 5-10C paraffins are converted under specified condition by being brought into contact with the aluminosilicate-zeolite catalyst comprising (1) a binder and (2) 2SM-5 or ZSM-11, which have an α-value of 5-25 (a now, activated catalyst having α-value of ≥50 when the catalyst is prepared at first, is preferable to partialy deactivate to the catalyst having α-value of ≤20 under a sufficient deactivating condition) to prepare aromatic hydrocarbons and oleffins at the same time.