PPARγ and in vivo tracing of tumors in animals, which increases the sensitivity of ultrasound imaging of thyroid tumors and can confirm the microscopic pathological basis of thyroid cancer lesions based on the anti-PAX8-PPARγ-targeted polymeric contrast agent, improves the early, non-invasive, and accurate diagnosis of thyroid cancer, and helps to explore the next step of molecularly targeted therapy for thyroid cancer based on it. Here, PAX8 is linked to thyroid tumor.