Abstract: With the rapid development of smart devices, some recording devices such as smart phones, recording pens and other means are more convenient and hidden to steal information, causing a great hidden trouble for individuals, enterprises and the government. The traditional countermeasures, background noise shielding and electromagnetic wave shielding, show their limitations. Playing loud noise to overwrite the conversation, the background noise shielding interferes with the normal progress of the conversation. Emitting high-power electromagnetic wave to shield the recording equipment, the electromagnetic wave shielding can only provide a limited shielding distance and effect. To solve the problems, a scheme of ultrasonic anti-recording screen was proposed based on acoustic parametric array theory to effectively shield the eavesdropping without the influence on the normal conversation. According to the acoustic parametric array theory, multiple high frequency ultrasonic waves were arranged to pass through a nonlinear system to produce low frequency acoustic signals under the nonlinear effect. According to this principle, the low-frequency wideband noise signal was generated at first, and then BASK modulation was carried out to modulate it to the high-frequency carrier. After power amplification, the noise signal was transmitted to the target recording device by transducer array. Experimental results show that recording functions of iPhone6s, Huawei p10, Huawei glory 9 and other smart phones can be effectively blocked with the maximum shielding distance ranging from 1~3 meter. Due to the universality of shielding principle, the proposed scheme can shield the terminals with recording function such as most models of smart phones and recording pens.