We study the spin-down changes of PSR B1859 + 07 over a period of more than 28 years of radio observation .
We identify that the time derivative of the rotational frequency ( \nu ) varies quasi-periodically with a period of \sim 350 days , switching mainly between two spin-down states .
The profile shape of the pulsar is correlated with the \dot { \nu } variation , producing two slightly different profile shapes corresponding to high- and low- \dot { \nu } states .
In addition to these two normal emission states , we confirm the occasional flare-state of the pulsar , in which the emission appears early in spin phase compared to that of the common normal emission .
The profile of the flare-state is significantly different from that of the two normal emission states .
The correlation analysis further shows that the flare-state is not directly linked with the \dot { \nu } changes .
With a simple emission beam model , we estimate the emission altitude of the normal emission to be 240 km , and explain the origin of the flare-state as an emission height variation from the leading edge of the beam .
We also argue that the emission of these states can be explained with a partially active beam model .
In this scenario , the trailing portion of the radio beam is usually active and the normal emission is produced .
The flare-state occurs when the leading edge of the beam becomes active while the trailing part is being blocked .
This model estimates a fixed emission altitude of 360 km .
However , the cause of the flare-state ( i.e .
the emission height variation , or the time-dependent activity across the radio beam ) is not easily explained .