Officers from 40 police forces nationwide took part in Operation Tharsley, a major two day crackdown on people who download indecent images of children.
A 40-year-old man was arrested for alleged indecent image offences at an address near Lincoln.
A search warrant also led to the arrest of a 57-year-old man in a village near Sleaford.
Last year the Internet Child Abuse Team, made up of six detectives, recovered computers containing more than 5 million child abuse images.
That was a significant increase on the 1.5 million seized the previous year.
Officers say this increase is partly down to their ability to better detect such crimes.