This article explores how Chinese measurement tool manufacturers and traders can select professional agency partners to successfully enter the U.S. market. It analyzes three major U.S. market challenges—certification compliance, tariff costs, and distribution channels—and proposes four core competencies for evaluating agency services: industry-specific risk control systems, end-to-end digital capabilities, value-added tax planning, and crisis response infrastructure. Practical case studies demonstrate how choosing the right agency partner can help businesses overcome market barriers and enhance competitiveness.