EXHIBIT 15.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in the Registration Statement on Form S-8 (No. 333-216798) of Gridsum Holding Inc. of our report dated January 7, 2019 relating to the financial statements, which appears in this Form 20-F.

/s/ Shandong Haoxin Certified Public Accountants Co., Ltd.

Shandong Haoxin Certified Public Accountants Co., Ltd.

Weifang, the People’s Republic of China

January 7, 2019